Have not seen this done before!

[Doby45]

SDI still teaches OW using tables

This is where you were wrong.

 

[Doby45]

This is from the actual Standards & Procedures. Nothing at all about tables, but amazingly a section regarding REQUIRED computer use.

7.10 Required Skill Performance and Graduation Requirements Students are required to successfully complete the following skills:

1. Swimming evaluation (Must be completed prior to any scuba skill being taught)
a. Distance swim of 200 metres non-stop using any stroke without the use of mask, snorkel or any swimming aids, or 300 metres non-stop using mask, snorkel, and fins
b. Survival swim / float of 10 minutes Note: If an exposure suit is worn for any of the above skills, the wearer must be neutrally buoyant at the surface.

2. Scuba skills
a. Scuba system assembly and disassembly
b. Weight system adjustment with proper weighting
c. Removal and replacement of weight system on the surface
d. Removal and replacement of weight system at depth

3. Pre-dive check of self and buddy

4. Partial mask clear at depth

5. Full mask clear at depth

6. Breathing and swimming underwater without a mask

7. Buoyancy compensator device (BCD) use:
a. Inflation and deflation (oral/power) at the surface
b. Inflation and deflation (oral/power) at depth
c. Removal and replacement at surface
d. Removal and replacement at depth

8. Buoyancy Control
a. Hovering
b. Controlled ascents
c. Controlled descents

9. Regulator use
a. Breathing, clearing, and recovery at the surface
b. Breathing, clearing, and recovery at depth

10. Underwater swimming; proper use of fins

11. Entries and exits
a. Shallow water entry
b. Deep water entry
c. Shallow water exit
d. Deep water exit

12. Snorkel use
a. Adjustment
b. Clearing; blast method
c. Regulator snorkel exchange at the surface
d. Surface snorkel swim in full equipment

13. Computer use
a. Reading and understanding data
b. Understanding functions of computer

14. Use of gauges

15. Underwater communications

16. Rescue techniques
a. Tired diver tows
b. Cramp relief

17. Out-of-air emergencies
a. Controlled swimming ascent
b. Alternate air source use; air sharing with a buddy while making a controlled ascent

18. Underwater Navigation

 

[johndiver999]

The real practical dangers of poor or no training in nitrox is going too deep, not checking the mix and assuming nitrox and setting a computer for nitrox when you are diving air.

If the recreational diver is supervised and only placed in areas with a hard bottom and agrees to a maximum time, and the tank is checked for percentage, I really see little issue with it. Of course it is trust me dive, but so is getting on a small sea going vessel, going on a zip line or getting on a skiing chair lift.

Most recreational participants have neither the inclination nor ability to realistically evaluate the true safety of these equipment related activities.

If the dive operator is giving out free nitrox, they must believe it enhances the customer’s experience, and probably their safety. After all, nitrox does nothing more than knock 15 or 20 feet off the effective depth.

 

[60plus]

Giving out computers even if divers do not know how to use them. This is a requirement of some dive ops insurers. If you have a 60 ft / 18m cert and you have an accident and your computer shows 61 ft the dive ops insurer does not have to pay out.
I know of reputable dive ops who give nitrox to divers without nitrox certs on conducted dives. I do not know the reason.

Gas composition measurement. I have virtually no experience of this as regards dive ops / nitrox. I do have a fair bit of experience of vehicle exhaust analysis, including set up after LPG conversion. Also experience of welding gas analysis and purge / vacuum chamber gas analysis. Gas analysers are not that reliable, can be affected by unanticipated factors and give variable results. Gas contamination although uncommon is more frequent than might be expected. I have known gases contaminated with oil and rust particles and significant percentages of wrong gases in cylinders. Carbon Monoxide and Oxygen sensors in analysers are often far from 100% accurate.

 

[Kharon]

... I do have a fair bit of experience of vehicle exhaust analysis, including set up after LPG conversion. Also experience of welding gas analysis and purge / vacuum chamber gas analysis. Gas analysers are not that reliable, can be affected by unanticipated factors and give variable results. Gas contamination although uncommon is more frequent than might be expected. I have known gases contaminated with oil and rust particles and significant percentages of wrong gases in cylinders. Carbon Monoxide and Oxygen sensors in analysers are often far from 100% accurate.

Sounds like analyzing air (not nitrox) tanks from a resort that does a ton of fills would be a crap shoot?

 

[60plus]

I am qualified to audit company quality assurance systems to BS5750 / ISO 9001 and have done quite a bit of this in the course of my previous employment. I point out that my experience is with industrial gases and automotive exhaust gases not diving gases. Any equipment is only as good as the people using it and the system that is in place for managing its use and maintaining it. It is far better to have nitrox analysers even if they occasionally give incorrect readings or are a few percent out. If a gas analyser is properly maintained and checked for accuracy (using a calibrating gas) before and after use it is highly unlikely it will give a false reading. However in an analyser is only used infrequently and left in a toolbox or typical workshop conditions and not tested immediately before and after use you should be much more wary of its output. I suppose when checking nitrox you know what the composition should be and therefore if you are checking a number of cylinders any incorrect blend should show up pretty clearly.

 

[CT-Rich]

I am qualified to audit company quality assurance systems to BS5750 / ISO 9001 and have done quite a bit of this in the course of my previous employment. I point out that my experience is with industrial gases and automotive exhaust gases not diving gases. Any equipment is only as good as the people using it and the system that is in place for managing its use and maintaining it. It is far better to have nitrox analysers even if they occasionally give incorrect readings or are a few percent out. If a gas analyser is properly maintained and checked for accuracy (using a calibrating gas) before and after use it is highly unlikely it will give a false reading. However in an analyser is only used infrequently and left in a toolbox or typical workshop conditions and not tested immediately before and after use you should be much more wary of its output. I suppose when checking nitrox you know what the composition should be and therefore if you are checking a number of cylinders any incorrect blend should show up pretty clearly.

The reference Gas is compressed air, 21%O2.

 

[Kharon]

I am qualified to audit company quality assurance systems to BS5750 / ISO 9001 and have done quite a bit of this in the course of my previous employment. I point out that my experience is with industrial gases and automotive exhaust gases not diving gases. Any equipment is only as good as the people using it and the system that is in place for managing its use and maintaining it. It is far better to have nitrox analysers even if they occasionally give incorrect readings or are a few percent out. If a gas analyser is properly maintained and checked for accuracy (using a calibrating gas) before and after use it is highly unlikely it will give a false reading. However in an analyser is only used infrequently and left in a toolbox or typical workshop conditions and not tested immediately before and after use you should be much more wary of its output. I suppose when checking nitrox you know what the composition should be and therefore if you are checking a number of cylinders any incorrect blend should show up pretty clearly.

Even though I am nitrox certified I don't use it for a number of reasons. Do you think I really need to analyze every tank I use - rentals from my LDS and unlimited air tanks on Bonaire? One of the reasons I don't use nitrox is that I don't want to be bothered with the calibration, analysis, logging, etc when my dives are between 30 and 60 feet, with average depth 30-40 feet. What about CO. If I've got to check every tank for gas mix and CO I'll probably go back to snorkeling.

 

[60plus]

Bearing in mind you have far more diving experience than me I am not sure i should advise you of anything. I was involved with the daily use of industrial gases for 36 years and in all that time there were relatively few incidents of gas contamination. If applied to diving gases the errors would probably have resulted in aborted dives and maybe a few days in hospital rather than a fatality. Nitrox for diving is a bit different though and that is probably why every cylinder should be tested before use. Excess oxygen could cause an explosion. Excess oxygen could also cause oxygen toxicity which would most probably be fatal.

 

[ChuckP]

About any contamination at depth could cause a fatality.